Multi-purpose operating unit attachment system

ABSTRACT

A multi-purpose turf machine ( 100 ) used primarily as a triplex turf mower includes a system for attaching an “operating unit” (e.g., a turf cutting unit) to a traction vehicle ( 102 ); and for moving the operating units, e.g., a pair of front cutting units ( 108   a ), between a working position and a transport position, the system utilizing a single actuator ( 224 ) to provide both vertical lifting as well as “wing-like” pivoting motion. The attachment system includes a female A-frame member ( 132 ) attached to the front cutting units ( 108   a ) and a mating male A-frame member ( 202 ) movably connected to the frame ( 101 ) of the vehicle ( 102 ). The machine ( 100 ) additionally includes a belt drive system to power the cutting units ( 108 ). The belt drive system provides correct belt tension between a driving pulley ( 230, 236 ) located on the vehicle ( 102 ) and a driven pulley ( 124 ) located on the end of each cutting unit ( 108 ) when the cutting units are in the working position. The drive system can additionally accommodate the wing-like pivoting motion of the front cutting units ( 108   a ) as they are moved from the working position to the transport position and back again. Finally, a preferred attachment system is highly versatile and easily permits removal and installation of a wide variety of operating units, e.g., cutting units, brooms, blowers, dump carts and dozer blades.

This application is a continuation in part of provisional applicationSer. No. 60/057,246, filed Aug. 29, 1997.

TECHNICAL FIELD

This invention relates generally to turf maintenance equipment, and oreparticularly to an improved system for attaching an “operating unit”(e.g., a cutting reel) to a traction vehicle.

BACKGROUND OF THE INVENTION

Although the present invention can be applied to a wide variety of turfmaintenance equipment, it is particularly well suited for use withmulti-purpose turf maintenance machines used primarily as power turfmowers. Although many types of power turf mowers are known, suchequipment may generally be classified according to the type of cuttingunit it employs. A rotary cutting unit usually includes one or morerigid, generally straight, steel blades rotated within a housing(“deck”) about a vertical axis to strike and sever the grass or othervegetation at a predetermined height above the ground. A reel cuttingunit, on the other hand, typically includes a reel having several curvedblades rotated about a horizontal axis. The curved blades of the reelwork in conjunction with a fixed blade, or “bedknife,” to shear thegrass in a scissorslike manner.

While rotary cutting units are suitable for many purposes, it isgenerally perceived that reel cutting units provide a higher qualitycut. The present invention relates primarily though not exclusively toreel-type turf mowers, and the remainder of the discussion will focusaccordingly.

Power turf mowing equipment may also be categorized based on the methodused to propel the cutting units. Generally, there are walk-behind,riding, and towed turf mowers. The present invention relates primarilyto riding turf mowers and, more specifically, those riding turf mowerswith three reel-type cutting units, generally referred to as “triplexmowers.”

Triplex mowers typically include a traction vehicle supported by aplurality of wheels, including one or more traction (i.e., powered)wheels; a prime mover supported by the vehicle frame and connectedthrough a transmission to the traction wheel(s); and three cutting unitspowered by the prime mover, two cutting units mounted generally ahead ofthe front wheel(s) and laterally offset about the longitudinal orfore-and-aft axis of the traction vehicle, and one cutting unit mountedgenerally between the front and rear wheels and laterally centeredbetween the front cutting units. Typically, the two forward cuttingunits of a triplex mower, being laterally and symmetrically offset,leave an uncut section therebetween during operation. Being centeredbetween the front cutting units, the rear cutting unit then spans theuncut section and overlaps the mowed path of both forward cutting units.Consistent mowing across the full span of the mower is thus obtained.

Triplex mowers further include a system designed to attach the cuttingunits to the vehicle. In addition to securing the cutting units to thetraction vehicle, the attachment system also permits lifting of thecutting units from their lowered, working position to their raised,transport position. In the working position, the attachment systempreferably permits the cutting units to “float” relative to the tractionvehicle. That is, the cutting units are independently and separatelysupported so that they can follow the contours and undulations of theground irrespective of the motion of the traction vehicle. In thetransport position, the front cutting units are typically raised suchthat the outer ends are pivoted upwardly (and sometimes inwardly) toreduce the overall width of the mower (the rear cutting unit istypically lifted only vertically). In this configuration, the mower ismore easily maneuvered between obstacles; e.g., trees and fences.Movement of the front cutting units between the working and transportpositions is often accomplished through simple pivotal motion. That is,each front cutting unit pivots about a horizontal or “wing” axis whichis parallel to the vehicle longitudinal axis and near the inboard end ofthe cutting unit. By properly locating the wing axis, the preferredrange of motion (i.e., movement between working and transport positions)is obtained.

In addition to mechanically securing the implement or “operating unit”to the traction vehicle, the attachment system preferably provides drivepower to the implement. Two different types of drive systems arecommonly utilized with triplex mowers. The first implement drive systemuses a hydraulic motor to drive each independent reel. The hydraulicmotor is usually mounted to one of the reel ends and connected by aseries of flexible hoses to a pump located on the traction vehicleframe. This drive system is advantageous in that the flexible hoseattachment can easily accommodate the range of cutting unit motionrequired during operation and during movement between the working andtransport positions. However, providing separate hydraulic motors foreach reel is costly. For this reason, some triplex mowers utilize a beltdrive system. Belt drive systems employ a driven pulley located on eachreel that is connected by a flexible drive belt to a driving pulleylocated on the traction vehicle. While more economical, belt drivesystems require an attachment system that provides the necessary belttension when the cutting units are in the working position yet does notinterfere with movement of the cutting units during operation (i.e.,floating) or during movement to the transport position. The presentinvention is primarily, though not exclusively, directed to a triplexmower having a belt drive system for supplying power to the cuttingreels.

While the attachment system of the present invention could be used witha dedicated, single-purpose turf mower, it is preferably used inconjunction with a multi-purpose turf machine. Such multi-purpose turfmachines, by definition, must accommodate other implements or “operatingunits” (e.g., blowers, rotary brooms, snow throwers and dozer blades) inaddition to reel cutting units. Some of these other implements or“operating units” generally require the ability to be either verticallylifted or “pitched” (about a transverse horizontal axis runninggenerally perpendicular to the vehicle's fore-and-aft longitudinalcenterline) rather than pivoted about a longitudinal horizontal axis, or“wing axis.” For example, in order to effectively transport a snowthrower or dozer blade, it must be vertically elevated from its workingposition, rather than pivoted about a “wing axis” as reel cutting unitstypically require. It is therefore beneficial for an attachment systemof a multipurpose turf machine to include the capability to either lift(or pitch) a given implement, or pivot it about a wing axis, or both.

Many different types of attachment systems that provide this dual motion(i.e., lift or pitching motion on the one hand, and a “wing” type motionon the other hand) have been tried over the years. With many attachmentsystems, one actuating device (e.g., hydraulic cylinder) is used toprovide the lifting or pitching motion, while another actuating deviceis used to provide the wing type motion. While such attachment systemshave proven to be adequate, the use of multiple actuating devices canadd considerable cost and complexity to the mower. Thus, an attachmentsystem that can accomplish the desired operating unit motion moreeconomically and with less complexity is highly desirable. Ideally, theattachment system can provide this dual motion with only one actuatingdevice (e.g., hydraulic cylinder).

Another preferred feature of an operating unit attachment system is theability to permit implements to be quickly and easily attached andremoved from the traction vehicle. Failure of the attachment system topermit easy attachment significantly reduces versatility of the machine.Although such quick-attach systems are known, many are generallyperceived to sacrifice quality of cut (when turf cutting units areinstalled) in favor of ease of attachment.

Thus, there are several challenges associated with attaching anoperating unit (e.g., a reel type cutting unit) to a multi-purpose turfmaintenance vehicle. The challenges include ease of attachment,simplicity of actuation, and a reasonable cost for the drive system. Theoperating unit attachment system of the present invention meets thesechallenges.

SUMMARY OF THE INVENTION

The present invention is directed to an attachment system for securingan implement or “operating unit” (e.g., a reel type turf cutting unit)to a traction vehicle. The attachment system connects the operating unitto the traction vehicle, powers the implement (if power is required forthe implement), and facilitates optimum movement of the operating unitfrom a working position to a transport position relative to the tractionvehicle; and the attachment system preferably includes a male member; afemale member substantially congruent to the male member, wherein themale member interlocks with the female member, thereby interconnectingthe operating unit to the traction vehicle; means for vertically raisingthe interconnected members and the operating unit; and means forpivoting the operating unit relative to the traction vehicle as theoperating unit is raised from its working position to its transportposition.

In a preferred embodiment, the attachment system includes an upwardlyconverging male member operatively connected to the traction vehicle,and an upwardly converging female member operatively connected to theoperating unit. And, in a most preferred embodiment, the male and femalemembers are A-shaped, in particular “A-frame” assemblies.

Another aspect of the invention is that there is preferably a firstdevice for vertically raising the interconnected male and female members(whether A-shaped or otherwise) and the operating unit; and a seconddevice for pivoting the operating unit relative to the traction vehicleas the operating unit is raised, wherein the pivoting device includes afirst contact member operatively connected to the operating unit and asecond contact member operatively connected to the traction vehicle,whereby interaction between the first and second contact members causesthe operating unit to simultaneously pivot as it is raised from itsworking position to its transport position.

Another aspect of a preferred attachment system relates to providingpower to the implement or operating unit. In a preferred embodiment thetraction vehicle prime mover powers at least one auxiliary drivingpulley, and the driving pulley is operatively connected to one or moredriven pulleys on the operating unit(s) by one or more drive belts; andincluded is a device for providing proper belt tension between thedriving pulley(s) and the driven pulley(s) when the operating unit is inthe working position. The belt tensioning means can include a tensionarm pivotally connected to the traction vehicle; an adjustable tie rodhaving a forward end operatively connected to the cutting unit and arearward end operatively connected to the tension arm; and a rubberbumper attached to the traction vehicle frame, whereby the rubber bumperforwardly biases the tie rod when the cutting unit is in the workingposition such that proper belt tension is applied when the cutting unitis in the working position.

Another embodiment of the invention is an attachment system for at leastone reel cutting unit; and a cutting unit lift arm for each cutting unithaving an outboard end pivotally attached to the cutting unit at anouter pivot, an inboard end, and a center pivot located between theinboard and outboard ends near the inboard end, wherein the center pivotprovides pivotal attachment of the lift arm to the female A-framemember, and wherein a “kicker roller” is mounted on the inboard end ofthe lift arm. The “kicker roller” interacts with a “stationary roller”mounted on the vehicle frame to cause the cutting unit(s) to pivot in“wing-like” fashion as each cutting unit is moved from its workingposition to its transport position.

Another aspect of the invention relates to how the operating unit ismoved from its working to its transport position. Preferably, theattachment system includes a hydraulic cylinder having a first endpivotally attached to the traction vehicle and a second end pivotallyattached to the male A-frame member, wherein the cylinder downwardlydisplaces the interconnected A-frame members when the cutting unit is inthe working position and upwardly displaces the A-frame members when thecutting unit is in the transport position; and the rollers discussedabove can interact to cause the operating unit to undergo sophisticatedmovements as A-frame members are being moved about by the hydrauliccylinder. Thus, potentially a single hydraulic cylinder is the only“active element” required to handle all of the implement moving tasks.

Finally, the “operating unit” referred to throughout this discussion canbe any grounds maintenance implement, e.g., a reel type cutting unit,rotary broom, debris blower, dozer blade, or even a dump cart.

BRIEF DESCRIPTION OF THE DRAWING

The invention will be further described with reference to the Drawing,wherein:

FIG. 1 is a left front perspective view of an operating unit attachmentsystem according to the present invention;

FIG. 2 is enlarged perspective view of the attachment system of FIG. 1with portions of the attachment system removed for the sake of clarity;

FIG. 3 is an exploded view of one major portion of the attachment systemof FIG. 1, the male A-frame assembly;

FIG. 4 is an exploded view of another major portion of the attachmentsystem of FIG. 1, the female A-frame assembly, taken from the front;

FIG. 4A is an exploded view of the female A-frame assembly taken fromthe rear;

FIG. 5 is an exploded view of a portion of the implement drive system,in particular the left half-shaft assembly;

FIG. 6 is an exploded view of another portion of the implement drivesystem, the right half-shaft assembly;

FIG. 7 is a front elevational view of the attachment system of FIG. 1with the cutting units in the transport position;

FIG. 8 is a left side elevational view of the attachment system of FIG.1 showing the belt tensioning mechanism of the implement drive system,with the cutting unit detached;

FIG. 9 is a side elevational view of the attachment system of FIG. 1with the left cutting unit removed and showing the belt tensioningmechanism with the cutting unit attached;

FIG. 10 is a top plan view of the attachment system of FIG. 1; and

FIG. 11 is a perspective view of a preferred multi-purpose turfmaintenance vehicle with alternative attachments.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the Drawing, wherein like reference numerals designate likeparts and assemblies throughout the several views, FIG. 1 shows aperspective view of a preferred turf maintenance machine 100 accordingto the invention. Machine 100 is a reel-type turf mower generally of thetype represented by the Grounds Pro™ 2000 triplex reel mower sold by TheToro Company, assignee herein, but those skilled in the art willappreciate that the present invention could be applied to other types ofturf maintenance equipment. Mower 100 includes a traction vehicle 102having a frame 101 (best shown in FIG. 2) supported by a pair of frontdrive wheels 104 appropriately coupled through a transmission (notshown) to a prime mover (also not shown). A rear steerable wheel 106,which may or may not be powered, supports the rearward end of vehicle102.

Turf maintenance machine 100 is, in its most preferred form, a highprecision yet versatile riding mower for use on sports fields. In theembodiment as shown in FIG. 1, there are two front cutting units 108 aspaced along a line generally perpendicular to a fore-and-aft orlongitudinal axis 103 of mower 100 and directly in front of drive wheels104; and a single rear cutting unit 108 b roughly centered between frontvehicle wheels 104 and also arranged along a line which is generallyperpendicular to the longitudinal axis 103 of the mower. As understoodby those skilled in the art, rear cutting unit 108 b is centered betweenand overlaps the front cutting units 108 a to handle the uncut strip ofgrass left therebetween.

Although the implement attachment system of the present inventionfocuses primarily on front cutting units 108 a rather than rear cuttingunit 108 b, it is worthwhile to note that both front and rear cuttingunits 108 are preferably nearly identical in all pertinent respects.However, the “a” and “b” suffixes will often be used where appropriateto clarify the invention. Further, in the preferred embodiment, the twofront cutting units 108 a and all related support structure areidentical mirror images of one another. Accordingly, Applicants oftenmake reference to parts and assemblies in the singular when, in fact,identical parts and assemblies exist on both left and right sides.

In the embodiment of mower 100 shown in FIG. 1, an operator sits in aseat 112 and steers the traction vehicle 102 by means of a steeringwheel 114 which can be manipulated to cause rear wheel 106 to pivotabout a vertical axis, thereby steering the vehicle. Various levers andpedals permit the operator to control the engine speed, cutting units(on/off, raise/lower), brakes, etc. The prime mover powers one or morehydraulic pumps which provide(s) hydraulic fluid to the wheel motors andthe cutting unit drive system, under control of variousoperator-controlled valves.

Although the particular construction of reel units 108 is, for the mostpart, not central to the invention, the basic components will bedescribed. Referring particularly to FIGS. 1, 7 and 8, a pair ofgenerally rectangular side plates 116 are located at opposite ends ofeach reel unit 108. Plates 116 are spanned at the top by a steel crosstube 118 (best viewed in FIG. 7) and at the bottom by a rear roller 121and a front roller 120. The front roller can be a so-called “wiehle”roller, having a series of circumferential grooves across its entirewidth. Also spanning side plates 116 is a horizontally centrally mountedrotatable reel 122. A driven pulley 124, as shown in FIG. 7, is coupledto reel 122 to provide power thereto. The standing grass blades aresheared off toward the bottom of the reel, at a stationary bedknife (notshown).

Cutting units 108 may also include several shields (not shown) whichhelp confine and direct the grass clippings. These shields are generallyconcentric to and offset from cutting reel 122.

Having described the traction vehicle and cutting units, attention willnow be directed to a system 105 used to attach front cutting units 108 ato traction vehicle 102. In the preferred embodiment as shown in FIG. 2,the attachment system 105 comprises a male A-frame assembly 200 movablyattached to vehicle 102 and a female A-frame assembly 130 which carriesfront cutting units 108 a. Additionally, the preferred attachment system105 includes a drive system 107 best viewed in FIGS. 5, 6, 7 and 9. Eachof these major components or assemblies is discussed separately below.

FEMALE A-FRAME ASSEMBLY 130

Referring now to FIG. 4, which depicts female A-frame assembly 130, afemale A-frame member 132 is centrally located between cutting units 108a (not shown) and pivotally connected therebetween by a pair of liftarms 134 (one per cutting unit). Lift arm 134 is a substantiallystraight member extending outwardly and transversely from female A-framemember 132. Lift arm 134 has an outboard end 136 and an inboard end 138.Outboard end 136 preferably includes a cylindrical tube 140 having anaxis that is both substantially perpendicular to a longitudinal axis 145running through lift arm 134 and generally parallel to the vehiclelongitudinal axis 103. Outboard tube 140 pivotally attaches to crosstube 118 of cutting unit 108 a (cutting unit 108 a is omitted from FIG.4 for clarity but is shown in FIG. 7).

At the inboard end 138 of lift arm 134 is an inboard cylindrical tube142. Tube 142 connects each lift arm 134 to female A-frame member 132and preferably permits wing type pivotal motion about an axissubstantially parallel to the axis of outboard cylindrical element 140.Tubes 140 and 142 establish pivots that permit pivotal movement throughthe use of conventional bushings and bearings. Inboard tube 142 mountswithin a clevis 141 in female A-frame member 132 as shown in FIGS. 4 and8. More specifically, inboard tube 142 is carried by a rod 143 thatspans clevis 141. In the preferred embodiment, a small gap 149, bestviewed in FIG. 8, exists between inboard tube 142 and clevis 141. Theability to freely pivot about the pivot joints formed by tubes 140 and142 ensures that cutting units 108 a maintain optimal ground contactacross their entire width regardless of lateral variations in turfelevation.

Referring still to FIG. 4, further details of inboard end 138 of liftarm 134 will now be described. In the preferred embodiment, lift arm 134is constructed of rectangular steel stock extending between tubularelements 140 and 142. Inboard of tubular element 142 is a rod 147 uponwhich freely rotates a short tubular “kicker roller” 144, furtherdescribed below. The purpose of the assembly consisting of rod 147 andkicker roller 144 is described below. In the preferred embodiment, rod147 has a longitudinal axis substantially coaxial with longitudinal axis145 of lift arm 134. In another embodiment (not shown), the longitudinalaxis of inboard rod 147 could be angled relative to axis 145 of lift arm134 (although both axes would typically remain coplanar) in order toaccommodate alternative reel cutting units. In either embodiment, kickerroller 144 is rotatably and coaxially mounted on rod 147 such thatkicker roller 144 is free to rotate thereabout. In the preferredembodiment, kicker roller 144 is constructed of hardened steel and isapproximately 1.5 inch in diameter. The purpose of kicker roller 144 isdescribed below.

In addition to supporting lift arms 134, female A-frame member 132includes a pair of adjustable tension members 146 and a pair of tensionsprings 148 best viewed in FIG. 1. With one end attached to cutting unit108 a and the other end adjustably attached to tension member 146, eachspring 148 adjustably counterbalances the weight of the associatedcutting unit 108 a. By adjusting the spring tension and thus the amountof counterbalance force provided by spring 148, and thus the downwardforce applied by the cutting units, ground following and quality of cutmay be optimized for a variety of turf conditions.

As evidenced in both FIGS. 4 and 4A, female A-frame assembly 130includes the vertically oriented A-shaped member 132; the horizontallyoriented rectangular and downwardly opening clevis 141; and atrapezoidal brace member 151 that has a vertical surface welded to thevertical A shaped member 132, and a horizontal surface welded to thehorizontal clevis 141. A-shaped member 132 is formed by two, upwardlyconverging C-shaped channels 150 welded to form the “A” shape. Eachchannel 150 has a hollow interior and three closed sides (i.e., the“underside” of each channel 150 is open). Referring to FIG. 8, channel150 has an interior depth 133 designed to accommodate a mating maleA-frame member 202 as described below.

While the preferred embodiment utilizes the mating A-frame configurationas described within, Applicants perceive that other shapes could be usedand still fall within the scope of the invention. For example, theA-frame could be truncated (i.e., channels 150 could terminate beforereaching the A-frame peak or apex). Or, each A-frame member could berectangular, for example, and not A-shaped at all. It is even perceivedthat the A-frames (or any of the other alternatives listed above) couldbe inverted (i.e., like a “V”-frame in the case of “V” shaped matingelements) and still function in a similar manner. However, inverting themating members would also require reversing the location of the malemember relative to the female member. For example, the female V-framemember would then be mounted to the traction vehicle while the maleV-frame member would attach to the operating unit. While Applicantsbelieve these alternative embodiments are encompassed within the scopeof the present invention, it is perceived that the mating A-frameconfiguration described herein is a preferred embodiment.

MALE A-FRAME ASSEMBLY 200

Traction vehicle 102 carries male A-frame assembly 200 which is bestviewed in FIGS. 2 and 3. In the preferred embodiment, male A-frameassembly 200 comprises the male A-frame member 202 operatively connectedto vehicle frame 101. Like female A-frame member 132, male A-framemember 202 is formed by two, upwardly converging tubes or “legs” 206welded together to form the A-frame shape. However, instead of aC-shaped cross-section, tubes 206 are preferably constructed ofrectangular steel tubing. As best viewed in FIG. 8, each tube 206 has anexternal width 207 slightly smaller than interior depth 133 of channel150 of female A-frame member 132, thus permitting male A-frame member202 to fit “within” female A-frame member 132. When so assembled, tubes206 of male A-frame member 202 are substantially congruent tocorresponding channels 150 of female A-frame member 132. That is, maleA-frame 202 can nest within female A-frame member 202 such that eachchannel 150 substantially overlaps corresponding leg 206. This geometry,in addition to supporting cutting units 108 a, also assists in aligningthe cutting units to the traction vehicle.

Still referring to FIG. 8, male A-frame assembly 200 additionallycomprises three rearwardly and upwardly extending J-shaped members 208and 210 rigidly attached to male A-frame member 202. Upper J-shapedmember 208 is integral (e.g., welded) to the top or “apex” of the maleA-frame member 202. Integrally attached to the lowermost end of eachtube 206 is a lower J-shaped member 210. In the preferred embodiment,J-shaped members 208 and 210 provide pivotal attachment of male A-framemember 202 to vehicle frame 101 via an upper A-frame pivot joint 212(located at the top of upper J-shaped member 208) and a lower A-framepivot joint 214 on each lower J-shaped member 210.

Extending rearwardly from upper pivot 212 is an upper lift link 216. Theaft end of link 216 pivotally attaches to vehicle frame 101 at an upperframe pivot joint 218. Pivotally attached to each lower A-frame pivotjoint 214 is a lower lift link 220. The aft end of each lower lift link220 extends rearwardly and attaches to vehicle frame 101 at a lowerframe pivot joint 222. Pivot joints 212, 214, 218, and 222 each permitrotation about parallel, transverse horizontal axes. When the implementis in its lowered, working position, links 216 and 220 are substantiallyhorizontal and male A-frame member 202 is in a substantially verticalplane, as shown in FIG. 8. Since the geometry of lift links 216, 220generally forms a parallelogram, male A-frame member 202 remainssubstantially vertically oriented even as the implement is moved to itstransport position (shown in phantom in FIG. 9).

Interposed between vehicle frame 101 and male A-frame 202 is a liftcylinder 224. While it is depicted as a dual-acting, hydraulic cylinder,those skilled in the art will recognize that any linear actuator (e.g.pneumatic cylinder, electric ball screw) will suffice. Referring to FIG.8, the base end of cylinder 224 is pivotally attached to vehicle frame101 at a base pivot (not shown) and the rod end of cylinder 224 ispivotally attached to male A-frame member 202 at upper A-frame pivotjoint 212. A series of flexible hydraulic lines (not shown) connectcylinder 224 to a hydraulic pump (also not shown). By operatormanipulation of a control lever connected to a hydraulic valve (notshown), cylinder 224 may be commanded to extend upwardly or retractdownwardly. Extension/retraction of cylinder 224 results in verticaldisplacement of male A-frame member 202. In the preferred embodiment,the transport position corresponds to maximum extension of cylinder 224while the working position corresponds to minimum cylinder extension.The preferred cylinder has a bore diameter of 60 mm (2.36 in) and astroke of 140 mm (5.51 in). However, other cylinder sizes may benecessary to accommodate variations in geometry and weight.

Although not integral to male A-frame assembly 200, the stationaryrollers will now be discussed. Referring generally to FIGS. 2, 7 and 8,a pair of stationary rollers 227 extend forwardly from the lower centerof vehicle frame 101 in a direction substantially parallel to thelongitudinal axis of the vehicle. In the preferred embodiment, eachroller 227 is constructed of hardened steel and is approximately 3inches in diameter. Each roller is rotatably attached to the fixedportion of vehicle frame 101 and does not move with male A-frame member202. In the preferred embodiment, each roller 227 is located slightlyabove its associated kicker roller 144 when female A-frame assembly 130is attached and in the working position. The function of stationaryrollers 227 and kicker rollers 144 is described below.

DRIVE SYSTEM

Directing the reader's attention to FIGS. 5 and 6, the cutting unitdrive system will now be described. The prime mover preferably providespower to cutting units 108 through a belt drive. In the preferredembodiment, the prime mover operatively powers a left half-shaft 228under operator command. Left half-shaft 228 receives power from theprime mover through a main pulley 231. A first drive pulley 230 isaffixed proximal to the inboard end of left half-shaft 228. Mountedopposite to left half-shaft 228 is a right half-shaft 232. A splinedcoupler 234 may be manually engaged between half-shafts 228 and 232 toprovide rotational power to the latter. Operatively connected to righthalf-shaft 232 is a second drive pulley 236 and a third or rear drivepulley 238. During operation, first and second drive pulleys 230 and 236provide rotational power to the front left and right cutting unitsrespectively via a pair of drive belts 229 (best viewed in FIG. 9) whilerear drive pulley 238 provides power to rear cutting unit 108 b via arear drive belt (not shown). Only when coupler 234 is engaged do seconddrive pulley 236 and third drive pulley 238 receive power.

The drive system also includes a belt tensioning assembly 240 (one perfront cutting unit) best shown in FIG. 9. Belt tensioning assembly 240is designed to provide the correct belt tension when cutting unit 108 ais in the operating position, yet not interfere with the movement of thecutting unit as it is moved to the transport position. In the preferredembodiment, the belt tensioning assembly comprises several components. Atension arm 242 is pivotally connected to frame 101 at a frame pivot244. Pivot 244 preferably permits pivotal motion about a horizontaltransverse axis such that tension arm 242 remains in a substantiallyvertical plane. At its lower end, tension arm 242 includes a lower pivotjoint 246. Operatively connected to pivot joint 246 and extendingforwardly therefrom is a tie rod 248. At its forward end, tie rod 248connects to the inboard face of side plate 116 at a pivot joint 250.Preferably, tie rod 248 has, at each end, a spherical bearing 249 whichpermits not only pivotal motion but motion out-of-plane as well. In thepreferred embodiment, spherical rod ends 249 are threaded to tie rod 248and secured with a jam nut (not shown). Thus, the overall length of tierod 248 is adjustable.

At its upper end, tension arm 242 is biased clockwise (as viewed in FIG.9) by a rubber bumper 252 which is braced against frame 101. Thisbiasing action causes the lower end of tension arm 242, and thus tie rod248, to apply a forward force to cutting unit 108 a. Thus, when cuttingunits 108 a are in the operating position, optimal drive belt tension isprovided.

OPERATION

Having described the various items that comprise the preferred operatingunit attachment system, attention will now be directed to the operationof mower 100. In the preferred embodiment, attachment of female A-frameassembly 130 to the traction vehicle is accomplished by first fullyretracting lift cylinder 224, thus placing male A-frame member 202 inits lowermost position as shown in FIGS. 2 and 8. The traction vehiclemay then be maneuvered so that the apex of male A-frame member 202 isgenerally beneath the apex of female A-frame member 130. By manipulationof a lever (not shown), the operator may hydraulically actuate liftcylinder 224 to a slightly extended position. This forces male A-framemember 202 to rise and engage female A-frame member 130 as shown in FIG.9. Due to the common angular configuration of C-shaped channels 150 andtubes 206, engagement of the A-frame members will automatically centerfemale A-frame assembly 130 as it is raised. This feature isparticularly beneficial when the male and female A-frame members areslightly offset in the lateral direction prior to extension of cylinder224. Upon complete engagement, a locking pin 152 best viewed in FIG. 2,is inserted through both A-frame members to prevent relative motiontherebetween. Once the A-frame members are secured, drive belts 229(which remain with the cutting units when removed) are attached to drivepulleys 230 and 236. The drive pulleys are accessible for belt mountingwhen splined coupler 234 is disengaged, thus exposing the inboard endsof each half-shaft 228 and 232. Once the belts are installed, splinedcoupler 234 can be engaged between the separate half-shafts, permittingpower transmission to second and third drive pulleys 236 and 238.

Tie rod 248 may then be attached to tension arm 242 at tension arm/rodpivot joint 246. As previously described, since rod ends 249 are inthreaded engagement with tie rod 248, altering the amount of threadengagement between rod ends 249 and tie rod 248 will change theeffective length of the tie rod. When cutting units 108 a are installedand in the working position, rubber bumper 252 rearwardly biases theupper end of tension arm 242, resulting in a constant forward force ontie rod 248. The drive belts are thereby tensioned sufficiently topermit efficient transmission of rotary power from drive pulleys 230,236 to driven pulleys 124. While Applicants have selected rubber bumper252, alternative ways to apply a forward-acting force (for example, aconventional compression spring) to cutting unit 108 a also fall withinthe scope of this invention.

The belt tensioning assembly (tie rod 248, rod ends 249, tension arm242, and rubber bumper 252) is designed to provide the correct belttension when cutting unit 108 a is in the operating position yet notinterfere with the movement of the cutting unit as it is moved to thetransport position. This is accomplished by permitting tie rod 248 tomove freely in the forward direction, a result of tension arm 242pivoting freely in the clockwise direction (as viewed in FIG. 9) abouttension arm pivot joint 244. Additionally, rod ends 249 permit tie rod248 to translate out-of-plane. Thus, when the cutting unit 108 a ismoved to the transport position, tie rod 248 will assume a skewedposition as shown in FIG. 7. This range of freedom provides optimal belttension in the operating position without unduly restricting the motionof cutting unit 108 a as it is raised.

Referring now to FIG. 7, during operation, cutting unit 108 a is in thelower or working position and lift cylinder 224 is in the retracted or“down” position. In this configuration, the A-frame members are in theirlowermost position, permitting full engagement of cutting unit 108 awith the ground. As the cutting unit traverses undulations in theground, pivot joint 140 permits the cutting unit to pivot about anintermediate horizontal axis to maintain optimal ground contact. Whenthe vehicle traverses more gently sloping terrain, pivot joint 142permits the entire cutting unit to pivot about a horizontal or “wing”axis located more central to the traction vehicle. Thus, cutting unit108 a maintains optimal ground contact regardless of turf undulations.Irrespective of cutting unit movement though, the A-frame members remainstationary relative to the traction vehicle during operation.

When the cutting operation is complete, the operator, throughmanipulation of a control handle (not shown), may selectively disengagethe belt drive system to prevent the rotation of cutting reel 122. Byselectively commanding the cutting units 108 a to the transportposition, lift cylinder 224 extends, forcing male A-frame member 202 torise. In the preferred embodiment, if the operator fails to manuallydisengage the belt drive system prior to raising the cutting units, aninterlock will disengage the system automatically. Stated alternatively,cutting units 108 may receive power only when in the operating position.

As shown in FIG. 7, when male A-frame member 202 is raised, femaleA-frame member 132 and attached lift arms 134 also rise due to theinterconnection of the A-frame members. As the lift arms rise, eachkicker roller 144 eventually contacts the lowermost portion of thecorresponding stationary roller 227. As the lift arms 134 continue torise, each kicker roller 144 is prohibited from further vertical motionby interaction with stationary roller 227. This interaction forces liftarm 134 to pivot about joint 142. When cutting unit 108 a has reachedits raised or transport position, pivot joint 142 has risen abovestationary roller 227 while kicker roller 144 has been restricted asdescribed. The resulting geometry of the lift arm/cutting unit is shownin FIG. 7.

As the cutting units are repositioned between the working and transportpositions, the distance between drive pulleys 230, 236 and drivenpulleys 124 changes accordingly. To prevent over-stressing of drive belt229 as each cutting unit 108 a is raised, tension arm 242 pivotsclockwise (as viewed in FIG. 9) about tension arm pivot joint 244 andallows forward motion of tie rod 248. When cutting unit 108 a begins topivot due to contact between kicker roller 144 and stationary roller227, spherical rod ends 249 permit tie rod 248 to translateout-of-plane. Thus, tie rod 248 does not constrain the motion of cuttingunit 108 a as it is repositioned.

However, as the cutting unit is further raised, drive belt 229eventually begins to tighten. If the belt tension becomes too great,cutting unit motion can be restricted. Thus, inboard pivot joint 142 isdesigned to permit lift arm 134 to slide rearwardly as the cutting unitis raised. That is, as the cutting unit 108 a is raised from the workingto the transport position, lift arm 134 is free to slide rearwardlyalong pivot 142 to the extent gap 149 permits. By sizing gap 149correctly, adequate rearward movement of cutting unit 108 a and lift arm134 is provided to prevent over-extension of drive belt 229. Gap 149,however, is not so large that excessive belt slack develops.

While the preferred embodiment may utilize hydraulic pressure withincylinder 224 to maintain the cutting units in their transport position,a transport latch (not shown) may be used to lock the outboard ends ofcutting units 108 a in their raised position. The use of the transportlatch ensures that the cutting units remain in the desired raisedposition even when hydraulic pressure is removed (i.e., mower is turnedoff).

Upon reaching a new site, the operator may remove the transport latch(if installed) and command cutting units 108 to their down or workingposition. In the preferred embodiment, actuator 224 is hydraulicallyretracted. However, other embodiments utilizing gravity retract (i.e.,single-acting cylinder) are also possible within the scope of thisinvention. Due to the configuration of the belt tensioning assembly, noadditional operator interaction is necessary prior to engaging thecutting units 108 a.

Referring now to FIG. 9, rear cutting unit 108 b is operativelyconnected to cylinder 224 by a cable 254 and a series of pulleys 256.When actuator 224 is raised, cable 254 causes rear cutting unit 108 b tomove to its transport position. Like front cutting units 108 a, atransport latch (not shown) may be used to lock cutting unit 108 b inits transport position if desired.

In order to disengage female A-frame assembly 130 from the tractionvehicle, it is first necessary to lower cutting units 108 a to theworking position. The operator must then remove tie rod 248 from tensionarm 242 at pivot 246. Splined coupler 234 may then be retracted ontoleft half-shaft 228, thereby exposing the inboard end of both left andright half-shafts 228 and 232. With tie rods 248 disconnected,sufficient slack in drive belts 229 exists to permit removal of thebelts from drive pulleys 230 and 236. Finally, locking pin 152 may beremoved from the A-frame members. The vehicle may then be “backed away”from the female A-frame assembly 130 and, in this case, cutting units108 a.

Installation of other implements or “operating units” (e.g., snowthrower, dozer blade) requires a procedure quite similar to thatrequired of the cutting units. As shown in FIG. 11, each implement hasan identical female A-frame member 202. However, unlike cutting units108 a, these other implements may not have a component like kickerroller 144. If so, no wing motion occurs as the implement is raised.That is, the implement is displaced in the vertical direction only.Thus, by including or excluding a component like kicker roller 144 froma particular operating unit, lift cylinder 224 can provide both verticallifting and, if desired, “wing-like” pivoting of the operating unit.

By isolating the second and third drive pulleys 236 and 238 (i.e.,disengaging splined coupler 234), first drive pulley 230 may be used topower alternative implements without unnecessarily powering righthalf-shaft 232. Thus, rear cutting unit 108 b is operativelydisconnected from the prime mover whenever other implements areinstalled. While this permits the efficient use of belt-drivenattachments, the vehicle of the preferred embodiment also providesadditional drive methods for maximum versatility. Specifically, a PTOshaft as well as conventional hydraulic connections are provided. Thisprovides the mower of the present invention with considerableflexibility regarding the implements it may accommodate.

Preferred embodiments of the invention are described above. Thoseskilled in the art will recognize that other embodiments are possiblewithin the scope of the invention. Variations and modifications of thevarious parts and assemblies can certainly be made and still fall withinthe scope of the invention. Thus, the invention is limited only to theapparatus and method recited in the following claims, and equivalentsthereto.

We claim:
 1. For use with a traction vehicle and an operating unit, asystem for operatively connecting the operating unit to the tractionvehicle and for moving the operating unit from a working position to atransport position relative to the traction vehicle, the systemcomprising: a) a male member; b) a female member substantially congruentto the male member, wherein the male member interlocks with the femalemember, thereby interconnecting the operating unit to the tractionvehicle; c) means for vertically raising the interconnected members andthe operating unit; and d) means for pivoting the operating unitrelative to the traction vehicle about a longitudinal axis substantiallyparallel to a longitudinal axis of the vehicle to provide lateralwing-type folding of the operating unit relative to the traction vehicleas the operating unit is raised from its working position to itstransport position.
 2. For use with a traction vehicle and an operatingunit, a system for operatively connecting the operating unit to thetraction vehicle and for moving the operating unit from a workingposition to a transport position relative to the traction vehicle, thesystem comprising: a) an upwardly converging male member operativelyconnected to the traction vehicle; b) an upwardly converging femalemember operatively connected to the operating unit and substantiallycongruent to the male member, wherein the male member interlocks withthe female member, thereby interconnecting the operating unit to thetraction vehicle; c) means for vertically raising the interconnectedmembers and the operating unit; and d) means for pivoting the operatingunit relative to the traction vehicle about a longitudinal axissubstantially parallel to a longitudinal axis of the vehicle to providelateral wing-type folding of the operating unit relative to the tractionvehicle as the operating unit is raised from its working position to itstransport position.
 3. For use with a traction vehicle and an operatingunit, a system for operatively connecting the operating unit to thetraction vehicle and for moving the operating unit from a workingposition to a transport position relative to the traction vehicle, thesystem comprising: a) a male member operatively connected to thetraction vehicle; b) a female member operatively connected to theoperating unit, wherein the male member interlocks with the femalemember to interconnect the operating unit to the traction vehicle; c) afirst device for vertically raising the interconnected male and femalemembers and the operating unit; and d) a second device for pivoting theoperating unit relative to the traction vehicle about a longitudinalaxis substantially parallel to a longitudinal axis of the vehicle toprovide lateral wing-type folding of the operating unit relative to thetraction vehicle as the operating unit is raised, comprising: i) a firstcontact member operatively connected to the operating unit; and ii) asecond contact member operatively connected to the traction vehicle,whereby interaction between the first and second contact members causesthe operating unit to simultaneously pivot as it is raised from itsworking position to its transport position.
 4. A system for attaching anoperating unit to a traction vehicle, the traction vehicle having aprime mover powering at least one auxiliary drive pulley, wherein thedrive pulley is operatively connected to the operating unit by a drivebelt, the system comprising: a) a male A-frame member operativelyconnected to the traction vehicle; b) a female A-frame memberoperatively connected to the operating unit, wherein the male A-framemember engages the female A-frame member to interconnect the operatingunit to the traction vehicle; c) a first device for positioning theoperating unit in either a working position or a transport position; d)at least one driven pulley operatively connected to the operating unitto receive power from the drive belt; and e) a second device forproviding proper belt tension between the drive pulley and the drivenpulley when the operating unit is in the working position, wherein thesecond device comprises: i) a tension arm pivotally connected to thetraction vehicle; ii) an adjustable tie rod having a forward endoperatively connected to the operating unit and a rearward endoperatively connected to the tension arm; and iii) a biasing memberattached to the traction vehicle and acting against the tension arm toforwardly bias the tie rod when the operating unit is in the workingposition such that proper belt tension is applied when the operatingunit is in the working position.
 5. A system for attaching an operatingunit to a traction vehicle, the traction vehicle having a prime moverpowering at least one auxiliary drive pulley, wherein the drive pulleyis operatively connected to the operating unit by a drive belt, thesystem comprising: a) a male A-frame member operatively connected to thetraction vehicle; b) a female A-frame member operatively connected tothe operating unit, wherein the male A-frame member slidably engages thefemale A-frame member to interconnect the operating unit to the tractionvehicle; c) means for positioning the operating unit in either a workingposition or a transport position; d) at least one driven pulleyoperatively connected to the operating unit to receive power from thedrive belt; e) means for providing proper belt tension between the drivepulley and the driven pulley when the operating unit is in the workingposition; and f) wherein the operating unit comprises: i) at least onereel cutting unit; and ii) a lift arm having an outboard end pivotallyattached to the cutting unit at an outer pivot, an inboard end, and acenter pivot located between the inboard and outboard ends proximal tothe inboard end, the center pivot providing pivotal attachment of thelift arm to the female A-frame member.
 6. The system of claim 5, whereina kicker roller is mounted on the inboard end of the lift arm.
 7. Thesystem of claim 6, wherein the positioning means comprises: a) ahydraulic cylinder having a first end pivotally attached to the tractionvehicle and a second end pivotally attached to the male A-frame member,wherein the cylinder downwardly displaces the interconnected A-framemembers when the cutting unit is in the working position and upwardlydisplaces the A-frame members when the cutting unit is in the transportposition; and b) at least one stationary roller attached to the tractionvehicle, such that as the A-frame members are upwardly displaced, thestationary roller interacts with the kicker roller, whereby the lift armand cutting unit are pivoted about the center pivot.
 8. The system ofclaim 7, wherein the belt tensioning means comprises: a) a tension armpivotally connected to the traction vehicle; b) an adjustable tie rodhaving a forward end operatively connected to the cutting unit and arearward end operatively connected to the tension arm; and c) a rubberbumper attached to the traction vehicle frame, whereby the rubber bumperforwardly biases the tie rod when the cutting unit is in the workingposition such that proper belt tension is applied when the cutting unitis in the working position.
 9. The system of claim 8, wherein theadjustable tie rod additionally comprises a spherical rod end at boththe forward end and the rearward end.
 10. The system of claim 9, whereinthe lift arm slidably communicates with the center pivot such that thelift arm and cutting unit can slide rearwardly along the center pivot asthe cutting unit is raised from the working position to the transportposition.
 11. A power turf mower having a prime mover powering at leastone auxiliary drive pulley, wherein the drive pulley powers at least onedrive belt, the mower comprising: a) a traction vehicle; b) a device forgrooming turf; and c) a system for operatively attaching the turfgrooming device to the traction vehicle, wherein the system comprises(i) a male A-frame member operatively connected to the traction vehicle;(ii) a female A-frame member operatively connected to the turf groomingdevice, wherein the male A-frame member engages the female A-framemember to interconnect the turf grooming device to the traction vehicle;(iii) an actuator for positioning the turf grooming device in either aworking position or a transport position; (iv) at least one drivenpulley operatively connected to the turf grooming device to receivepower from the drive belt; and (v) a second device for providing properbelt tension between the drive pulley and the driven pulley when theturf grooming device is in the working position.
 12. For use with atraction vehicle and an operating unit, a system for operativelyconnecting the operating unit to the traction vehicle and for moving theoperating unit from a working position to a transport position relativeto the traction vehicle, the system comprising: a) at least one framemember operatively connected to the traction vehicle for verticalmovement; b) a lift arm operatively connected to the operating unit forcarrying the operating unit, the lift arm having a first pivotalconnection to the at least one frame member for pivotal, wing-typefolding of the operating member about a longitudinal lift arm axis thatis substantially parallel to a longitudinal axis of the tractionvehicle; c) a powered actuator for vertically moving the at least oneframe member relative to the traction vehicle to thereby vertically movethe lift arm and the operating unit carried thereon between a loweredworking position and a raised transport position; and d) a verticallyfixed contact member carried on the traction vehicle and positioned tohave an abutting engagement with the lift arm during vertical upwardmotion of the lift arm as the operating unit moves upwardly from itslowered working position towards its raised transport position, theabutting engagement between the stationary contact member and the liftarm being so located as to pivot the lift arm about the longitudinallift arm axis such that the pivotal, wing type folding of the operatingunit is automatically provided by the abutting engagement of thestationary contact member and the lift arm when the at least one framemember is moved vertically upwardly by the powered actuator.
 13. Thesystem of claim 12, wherein the powered actuator is a linear actuator.14. The system of claim 13, wherein the linear actuator is a hydrauliccylinder.
 15. The system of claims 12, wherein the vertically fixedcontact member is a rotatable roller carried on the traction vehicle ina vertically fixed position.
 16. The system of claim 15, furtherincluding a rotatable roller carried on the lift arm and verticallymovable with the lift arm as the at least one frame member movesvertically upwardly, wherein the rotatable roller carried on the liftarm has the abutting engagement with the rotatable roller carried on thetraction vehicle at some point during vertically upward motion of thelift arm and the operating unit carried thereon.
 17. The system of claim16, wherein the rotatable roller carried on the lift arm is located onone end of the lift arm, and the operating unit is carried on the otherend of the lift arm.
 18. The system of claim 17, wherein the operatingunit is carried on the other end of the lift arm by a second pivotalconnection that is substantially parallel to the longitudinal axis ofthe traction vehicle to permit the cutting unit to tilt or rock relativeto the lift arm as the lift arm also tilts or rocks relative to the atleast one frame member about the first pivotal connection when theoperating unit is in its lowered working position, thereby to allow theoperating unit to follow changes in ground contour.
 19. The system ofclaim 18, wherein the second pivotal connection of the operating unit tothe lift arm is substantially parallel to, but spaced from, the firstpivotal connection of the lift arm to the at least one frame member. 20.The system of claim 19, wherein the first pivotal connection of the liftarm to the at least one frame member is located on the lift arm betweenthe rotatable roller carried on the one end of the lift arm and thesecond pivotal connection of the operating unit to the lift arm carriedon the other end of the lift arm.
 21. The system of claim 12, whereinthe at least one frame member comprises first and second interlockingframe members, the first interlocking frame member being verticallymovable relative to the traction vehicle and the second interlockingframe member carrying the lift arm and the operating unit.
 22. Thesystem of claim 21, wherein the first interlocking frame member is amale frame member and the second interlocking frame member is a femaleframe member that is substantially congruent in shape to the male memberto allow the male and female frame members to nest and interlock withone another.
 23. The system of claim 22, wherein the male and femaleframe members are A-shaped.
 24. For use with a traction vehicle and anoperating unit, a system for operatively connecting the operating unitto the traction vehicle and for moving the operating unit from a workingposition to a transport position relative to the traction vehicle, thesystem comprising: a) at least one frame member operatively connected tothe traction vehicle for vertical movement; b) a lift arm operativelyconnected to the operating unit for carrying the operating unit, thelift arm having a first pivotal connection to the at least one framemember for pivotal, wing-type folding of the operating member about alongitudinal lift arm axis that is substantially parallel to alongitudinal axis of the traction vehicle; c) a powered actuator forvertically moving the at least one frame member relative to the tractionvehicle to thereby vertically move the lift arm and the operating unitcarried thereon between a lowered working position and a raisedtransport position; and d) a system to pivot the lift arm about thelongitudinal lift arm axis to provide the pivotal, wing type folding ofthe operating unit when the at least one frame member is movedvertically upwardly by the powered actuator; e) at least one drivenpulley operatively connected to the operating unit to receive power froma drive pulley on the traction vehicle; and f) a system for providingproper belt tension between the drive pulley and the driven pulley whenthe operating unit is in the working position, the system including aforwardly biased tie rod acting between the traction vehicle and thedriven pulley to force the driven pulley forwardly to maintain belttension, the tie rod having spherical rod ends at each end to allow thetie rod to change planes relative to the operating unit as the operatingunit experiences the pivotal, wing-type folding motion.
 25. The systemof claim 24, wherein the lift arm slidably communicates with the firstpivotal connection such that the lift arm and operating unit can sliderearwardly along the first pivotal connection as the operating unit israised from the working position to the transport position.